<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>

<select name="" id="">
    <option value="i">年</option>
    <script>
        for(var i=1990;i<=2020;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

<select name="" id="">
    <option value="">月</option>
    <script>
        for(var i=1;i<=12;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

<select name="" id="">
    <option value="">日</option>
    <script>
        for(var i=1;i<=31;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

<select name="" id="">
    <option value="">时</option>
    <script>
        for(var i=1;i<=24;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

<select name="" id="">
    <option value="">分</option>
    <script>
        for(var i=1;i<=60;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

<select name="" id="">
    <option value="">秒</option>
    <script>
        for(var i=1;i<=60;i++){
            document.write("<option>"+i+"</option>");
        }
    </script>
</select>

</html>